Analysis of thermodynamic losses in ground source heat pumps and their influence on overall system performance

32nd UIT (Italian Union of Thermo–fluid-dynamics) Heat Transfer Conference

物理学;力学

Casarosa, C.^1 ; Conti, P.^1 ; Franco, A.^1 ; Grassi, W.^1 ; Testi, D.^1

Department of Energy, Systems, Territory and Constructions Engineering (DESTEC), University of Pisa, Largo Lucio Lazzarino, Pisa

56122, Italy^1

关键词: Borehole heat exchangers;    Earth heat exchangers;    Efficiency parameters;    Heating and cooling;    Overall efficiency;    Technological improvements;    Thermal and hydraulic performance;    Thermal Performance;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/547/1/012006/pdf
DOI  :  10.1088/1742-6596/547/1/012006

学科分类：力学，机械学

来源: IOP

【 摘 要 】

The present work aims at identifying the relative influence of GSHP subsystems (viz. ground source, earth heat exchangers, heat pump unit, pumping devices) on the overall efficiency and the limits to which technological improvements should be pushed (because, beyond these limits, only minor benefits may be achieved). To this end, an analysis of thermodynamic losses is conducted for a case study, followed by a sensitivity analysis on the heat pump unit thermal performance. Primary energy consumptions of nine configurations with different combinations of ideal and real subsystems are compared. The completely ideal system is used as the reference to normalize energy consumptions and obtain a dimensionless efficiency parameter. The results show that-when a proper design methodology is employed-the performance of the borehole heat exchangers slightly affects the overall efficiency. On the contrary, the thermal response of the ground and the thermal and hydraulic performances of the heat pump unit are key factors. Finally, a sensitivity analysis is conducted by increasing the heating and cooling efficiencies of the heat pump device.